1. Field of the Invention
The present invention is related to an extension member for a cutting tool for cutting a workpiece wherein there is relative cutting motion about an axis of rotation between a cutting member or plate mounted upon a tool shank and a workpiece. The coolant is supplied from a coolant supply means to the cutting member by means of aligned bores in a coolant supply member, coolant supply ring, extension member and a tool shank.
2. Description of the Prior Art
Presently, it is known to supply a cooling medium to a rotating cutting tool from a coolant supply means to a cutting member. For example, one known apparatus is described in U.S. Pat. No. 4,392,761 to Eckle. The rotary machinery tool described in the Eckle patent includes a coolant delivery system wherein coolant is supplied from a supply pipe through a series of bores to the cutting members or plates. The coolant is supplied during the cutting operation. The Eckle apparatus is particularly useful in those applications where the cutting tool performs a number of machining operations one after the other upon the same workpiece. In such operations, different cutting plates are used for different cutting operations on the same workpiece. It is highly desirable to automatically interchange the cutting plates throughout the process. Ordinarily it is necessary to disconnect and then reconnect the coolant supply system each time the cutting plates are changed. An object of the Eckle apparatus is to provide a system of the type described therein which provides automatic coupling of the coolant delivery apparatus during the cutting plate interchanging process. This is done by supplying a cooling medium to the cutting plates using a supply ring which is automatically connected to and disconnected from a coupling head during cutting plate changes. More particularly, when one cutting member has been replaced by another and the tool shank is caused to rotate, the supply ring is designed to rotate in the same direction by the friction between the tool shank and the supply ring which is positioned on the tool shank. In this manner, a sealing surface of a coupling piece radially projecting from the supply ring comes into engagement with a sealing surface of a coupling head so that coolant can pass through bores in the coupling head, coupling piece and supply ring and then on through a bore in the tool shank to the cutting members. In passing through the bore in the tool shank the coolant first passes through one or more radially oriented tool shank bores which intersect with an axially oriented tool shank bore. In particular, the coolant flows from the bore in the supply ring, through the radial bore or bores in the tool shank and then through the axial bore in the tool shank to be emitted at the cutting members. In such apparatus the coolant is flowing from a stationary supply ring bore to the radial bores of the type referred to, such radial bores extending into a rotating tool shank. The effect of the rotation of the tool shank is to subject the coolant entering the radially oriented tool shank bores to centrifugal force which tends to resist the flow of the coolant towards the axial bore of the tool shank.
In such prior art apparatus, the tool shank is coupled directly to the drive spindle, the tool shank being inserted into a mating aperture to assure a satisfactory coupling. If a tool shank having a larger or smaller diameter is used, a different machine must be used or the drive spindle of the existing machine must be replaced with one having a correspondingly larger or smaller mating aperture. This is undesirable in that not only is it necessary to maintain in stock a full range of drive spindles but changing from one spindle to another can be a time consuming process. In addition, since the tool shank is coupled directly to the drive spindle, each tool shank put into service must include means for diverting the coolant from a supply ring to the axial bore of the tool shank. In other words, each tool shank requires one or more radial bores in addition to the axial bore which extends to the cutting members.
It is desirable to eliminate the need for stocking a plurality of tool shanks requiring radial as well as axial coolant supply bores, and a plurality of drive spindles of varying dimensions. To this end it is desirable to provide an extension member which serves as a coupling between a drive spindle and a tool shank. It is further desirable to provide such an extension member which tends to draw the coolant towards the longitudinal axis of the axial bore of the extension member during rotation thereof. In addition, it is desirable to provide such apparatus wherein a positive scooping effect serves to further pull the coolant towards the longitudinal axis of the axial bore of the extension member during rotation. It is also desirable to provide such machinery wherein the centrifugal force acting against the coolant is resisted.